1. Field of the Invention
This invention relates to decoring saws and to meat processing equipment and more particularly to meat processing saws and to methods for their use.
2. Related Art
Pig processing has traditionally been a manually intensive industry. Even in a modern plant, hundreds of workers use hand held knives or hand held electric saws to cut up the pork carcass.
In order to understand pork processing, it is useful to first understand the relevant portion of the anatomy of a pig. The spine of a pig typically includes 7 cervical vertebrae, 14 thoracic vertebrae and 7 lumbar vertebrae. The first cervical vertebra is commonly referred to as the "atlas bone." The point of connection between the skull and the atlas bone is often referred to as the atlas joint. Pigs typically have 14 ribs that depend from the spine in the region of the thoracic vertebrae. Spinuous processes, called featherbones, extend from and above each of the 14 thoracic vertebrae. Pigs that are raised for food vary in size and weight, typically ranging from 170 pounds to 370 pounds on the hoof (prior to slaughter.)
In a modern processing plant, a pig is eviscerated, the head is removed and the carcass is then split into two halves longitudinally along the backbone. Each half is then cut in two creating the shoulder and the hindquarter.
One particularly difficult portion to process is the shoulder portion, because removal of the backbone is required and the atlas bone is much bigger than the other vertebrae. In addition, because the pigs vary in size, pork shoulders vary in size and weight, often ranging between 22 and 49 pounds. A typical pork shoulder will include all of the cervical vertebrae, several thoracic vertebrae, and between 2 and 4 ribs, depending on customer order specifications. Typically the backbone, the featherbones and the ribs are removed from the pork shoulder by a worker using a hand held knife before the shoulder moves on for further processing. In some processing plants, as many as 7 butchers are employed on each shift to accomplish just this task. It normally takes about 7 seconds to manually debone the spine from each shoulder. It is a repetitious process, as a large processing plant may process more than 1000 pigs per hour, and thus more than 2000 pork shoulder per hour. The repetitive motions of the wrist and shoulder required for deboning pork shoulders sometimes cause cumulative trauma disorder to the worker, called a "lifter" who "lifts" the spine from the shoulder. The skeletal system that is removed by the lifter is then given to another worker called a "robber" for further processing. The "robber" removes most of the meat that remains on this skeletal system, typically by use of a hand held electric saw such as a Wizard Model 620. Vibrations from an imbalanced Wizard saw can also cause problems for the robbers. A better method is needed to reduce or eliminate the need for lifters and robbers and thus reduce the incidence of cumulative trauma disorders in the workforce. In addition, it would be desirable to leave more meat with the shoulder, as that meat sells for more than the robbed meat, the robbed meat typically going instead into sausage or pizza toppings or the like.
A better system is needed.